<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>dowhile循环语句</title>
<script language="javascript">
var i=0;
var str="6";
do{str="0"+str;i++;}
while(i<4);
document.write(str+" ");
</script>
</head>
<body>

</body>
</html>